The present invention relates generally to the field of chemical and/or biological detection. More particularly, the present invention provides a useful and novel system and method for detecting target toxic industrial chemicals, chemical or biological materials.
Chemical detection finds a wide variety of applications, such as detection of toxic industrial chemicals used in industrial and manufacturing applications, law enforcement and anti-terrorist efforts, environmental and agricultural contamination monitoring, medical diagnosis, and detection of chemical warfare agents.
The usefulness of carbon nanotube (CNT) structures in the field of chemical detection has been demonstrated. CNTs are molecular-scale ‘wires’. CNTs-based sensors are capable of detecting small concentrations of gas molecules. The conductance of CNTs can be substantially increased or decreased by exposure to certain gas molecules. Reference: Nanotube Molecular Wires as Chemical Sensors; Jing King, et al.; Science Magazine; Vol. 287; Jan. 28, 2000. Therefore, by measuring the change in an electrical property of a CNT sensors, such as resistance, capacitance, voltage or conductance, it is possible to detect the presence of a chemical that drives a change in that electrical property, and to identify the present chemical by comparing the magnitude, rate and direction of change of the electrical property to those changes known to result from exposure of the sensor to a particular chemical or biological agent.
While fixed sensors may utilize CNT structures to provide some amount of chemical detection, it can often be impractical to mount these sensors at locations throughout a manufacturing facility, combat zone, or other location so as to assure each worker/soldier is free from chemical exposure. Hence, what is needed is a sensor that is small and light enough to be easily carried around by a person, and yet is inexpensive enough such that a large number of workers/soldiers can be provided with one. A disposable configuration of the badge allows the user to dispose of it when contaminated with chemicals after an alarm event.